1. The Field of the Invention
The present invention generally relates to a device which functions as a polarization beam combiner and an isolator, and more particularly, a device that can combine two beams of polarized light into one beam and provide optical isolation in the reverse direction.
2. The Related Technology
Polarization beam combiners (“PBCs”) and optical isolators are prevalent in modem optical communications systems. PBCs, which combine two plane-polarized optical signals into a single combined signal, and optical isolators, which prevent the back-reflection of an optical signal, are employed as separate components in a variety of optical apparatus, including optical amplifiers, transceiver modules, etc.
As mentioned, one application where both a PBC and optical isolator can be used is in an optical amplifier, such as Raman amplifier or erbium-doped fiber amplifier (EDFA). These amplifiers are used to increase the strength of an optical signal to enable its transmission over large distances. A PBC is typically employed within the amplifier to combine polarized signals from two pump lasers into a combined signal for use in amplifying a data-containing main signal. Correspondingly, an optical isolator can be used to prevent back-reflection of the polarized signals back toward the pump lasers in order to optimize their operation.
As the size of such devices is progressively reduced due to advancements in technology, new means are continually being sought to minimize the amount of space occupied by components located within the device. Thus, to the extent that the space requirements of PBCs and optical isolators can be minimized, the utility of optical amplifiers and similar devices is improved.
Concurrent with the above concern is the ever-present aim of reducing the complexity of optical devices, including optical amplifers, PBCs, optical isolators, etc. To the extent that an optical device can be simplified in design, the cost to produce the device is reduced while its utility in a greater number of applications is increased. As such, common optical devices, such as optical amplifiers that include numerous interior components, present a particular challenge in terms of maximizing device simplicity.
In view of the above, a need exists in the art for an optical device that overcomes the above challenges. In particular, a need exists for an optical device that can perform polarization beam combination operations while also reducing or eliminating optical back-reflection. Furthermore, any solution to these needs should be implemented in a simple design that is able to reduce the overall complexity of the apparatus or device in which the solution is disposed.